1. Field of the Invention
This invention relates to annular shaft seals of the type including an elastomeric sealing element bonded to a metal shell having a guard or scraper portion, and in particular to it an improved method for making the same.
2. Description of the Prior Art
Annular shaft seals including an elastomeric sealing element bonded to a metal shell having a guard or scraper portion and generally having the arrangement shown in FIG. 1 are known in the prior art. However, the prior art method for making such a seal requires the three separate steps of: (1) piercing the metal shell prior to molding, (2) carrying out the molding process in which a blank prep form of elastomer is molded to provide a seal body bonded to the shell and having a sealing element with a lip, and (3) then subsequent to the molding process, the previously pierced I.D. edge of the scraper or guard is sharpened in a honing operation.
It is an object of the present invention to provide an improved method for making such a shaft seal which overcomes the problems in the prior art of using three separate steps to produce the sharp I.D. edge of the guard or scraper. It is a further object of the present invention to provide a method for making such a shaft seal in which a sharp I.D. edge of the guard or scraper is produced in a single step simultaneously with the molding step by "piercing" the sharp I.D. edge during the molding operation.